Field of the Invention
Embodiments of the present invention relate to a display device, and particularly to a thin film transistor assemble, an array substrate and a method of manufacturing the same, and a display device including the array substrate.
Description of the Related Art
Thin film transistors, which are currently widely used in a thin film transistor liquid crystal display (TFT-LCD) display device, an Organic Light Emitting Diode (OLED) display device and an Active Matrix Organic Light Emitting Diode (AMOLED) display device, mainly include amorphous silicon thin film transistors and poly-silicon thin film transistors. Low temperature poly-silicon (LTPS) technology has been applied in manufacturing processes of a thin film transistor display, in which an amorphous silicon film is transformed into a poly-silicon film by an excimer laser annealing process. Compared to the amorphous silicon (α-Si), a mobility ratio of the poly-silicon film produced in this way has been increased by a factor of 100. For example, the electron mobility ratio is increased up to 200 cm2/V-sec or more. Thus, the area of the thin film transistors can be effectively reduced and aperture ratio of a display is increased. Further, the total power consumption of the display is decreased while brightness thereof is improved. In addition, a display produced by means of LTPS technology has an improved response time, a higher revolution and better image displaying quality.
Generally, in a top gate thin film transistor comprising an active layer that is formed by using the poly-silicon film, a source electrode, a drain electrode and a data line connected to the source electrode thereof are formed on a glass substrate, a gate electrode is formed above the source electrode and the drain electrode while the active layer is located between the gate electrode and the source and drain electrodes. In addition, a light shielding layer is provided between the active layer and the glass substrate to block illumination of light introduced from the glass substrate on the active layer, which illumination will affect electrical characteristic of the low temperature poly-silicon film used to form the active layer. During production of the array substrate, a plurality of patterning processes are usually needed to respectively form the source electrode, the drain electrode, the light shielding layer and the gate electrode, in which masks for the patterning processes each have different patterns. As the masks are expensive, the process of manufacturing the array substrate including a plurality of patterning processes is complex and high in cost.